This invention relates to a noise abatement wall and more particularly to a noise abatement wall in the form of a precast, prestressed concrete sound wall capable of standing on its own while providing both aesthetically pleasing appearance and sound damping effect for noise created by traffic.
Roads, and especially interstate highways or tollways create a substantial amount of noise due to the high volume of traffic thereon. It is common for a residential community to be built close to such a road structure. It is also common for such a road structure to be built close to a prior existing residential community.
In the magazine entitled Wall Journal of September/October 1993, figures indicate that a heavy truck produces about ten times the noise energy of a passenger car. In other words, ten passenger cars produce the noise energy of one heavy truck. It is desired, and even required, to reduce this noise and provide for aesthetically pleasing comfort for nearby residential areas.
No matter how that proximity occurs, the noise from the road structure can easily disturb the tranquility of a community. It is desired to minimize the noise and disturbance to the community while maintaining the closeness of the road and the efficiency thereof. Such closeness of efficient travel to a community provides for more efficient transportation and greater use of assets. It also provides terrific environmental advantages for such actions, due to reduced travel time and efficient vehicle use among other reasons.
Unfortunately walls designed to decrease the noise have a tendency to be expensive without achieving the desired results of noise abatement. Typically, if such a wall is flat cast and moved into place, the wall must then be supported until it is cured. The support is a complicated, costly structure in order to stand vertically as required. The complicated wall support structure, not only adds to the expense, but detracts from the aesthetic qualities of the wall.
An attempt to cast the wall in place is inefficient because of the required molding and structure set up. Accordingly, it is desired to achieve the production of the walls in an efficient fashion while obtaining the desired results.
Added to that difficult combination is the requirement that the wall must reflect sound. If sound can be reflected away from an area, great advantages occur from the resulting relative reduction of noise in the area desired to be protected from that noise.
It is highly desirable that such a wall be simply and easily produced. That wall must also be both attractive and cost effective. This is a difficult combination of factors to achieve.
Further advantages are obtained if a noise abatement wall can be moved after installation. This movement, of course, is necessary when widening of the road is considered. If the walls can be moved and reused, great advantages are obtained in that savings become substantial in the construction of the highway widening project.
Typical surfaces desired for these panels or wall sections include rake, broom, or exposed aggregate. It is desired, however, to achieve a number of additional different surfaces. This requirement of different surfaces for different wall sections, and even for a different surface on each side of a panel thereof creates difficulty for the efficient formation of these surfaces. Not only must the mold be adjusted to form the desired surface, the mold must be adjusted efficiently and with minimal cost.
A noise abatement wall is also subject to high wind loads. The noise abatement wall must supported sufficiently to withstand the windloads.
The size and weight of a wall section make it difficult ship and handle a wall section. Once the sections are delivered, it is necessary to have them simply installed.